Boot Portable Live USB Linux on Older Hardware

Your Linux is Portable, But Where's the Port?

March 11, 2011

By
Emery Fletcher

Portable USB Linux distros are wonderful go-anywhere Linuxes for troubleshooting and repair. The catch is older hardware doesn't always support booting from a USB stick-- but there is a workaround called Plop Boot Manager
I don't usually offer my opinions on purely technical matters related
to computers and systems, because I don't consider myself an
especially technical person. On the other hand, when I come across
something technical that makes a major improvement in my life at the
computer, I do my best to advertise it to others. The latest item to
perform that minor miracle for me has been the Plop Boot Manager, and
the need arose when I first put a Linux distro on a thumb drive.

There is a lot to be said for the Linux-on-a-stick concept, a USB
thumb drive with a bootable Linux distro on it. The small size of the
system image many distros offer means that even a modest thumb drive
can hold the image and still provide a healthy amount of space for the
persistence you need to save your configuration and the work you do on
it. Further, the capacity of thumb drives is increasing so fast that
the largest now exceed the storage available on the 40 to 80GB hard
drives that used to be regarded as the business standard. All the
potential of a thumb drive distro can be put to work or installed on
any computer that will boot from a thumb drive.

And there's the rub. Modern PCs, those built within the last few
years, almost always have a BIOS that can be set to accept boot
loading input from a CD, a DVD, or a USB drive. But out in the world
there are still a lot of fully working older computers that simply
can't read a boot loader file from a USB. That's really a shame,
because so many Linux distros are light enough that they can be agile
and productive on the modest resources of those old but healthy
machines.

The fundamental problem is a straightforward matter of connectivity.
The USB contains digital information which can handle the later stages
of bootstrapping an operating system using the available resources of
the old machine; the BIOS can access the firmware in the CMOS to
supply the very first stage of the boot process; and the BIOS and the
USB each use a language the other can understand. The problem is that
there is just no way for the existing BIOS to accept input from the
USB port.

As a relative newcomer to computers in general, my first response was
to accept that condition as absolute. I knew just enough to be aware
that a BIOS is not something to be dealt with casually. When you come
right down to it, altering the BIOS is potentially the most dangerous
activity you can do on a computer. Botching your GRUB boot loader is a real
annoyance; losing your MBR requires major digital surgery; but a
wrecked BIOS can render your motherboard useless.